import os
import time
import fcntl
import ctypes
import warnings

from ctypes import c_uint16 as _u16
from ctypes import c_int16 as _s16
from ctypes import c_uint32 as _u32
from ctypes import c_int32 as _s32
from ctypes import c_int64 as _s64
from concurrent.futures import ThreadPoolExecutor

from typing import List

import pyglet

from .evdev_constants import *
from pyglet.app.xlib import XlibSelectDevice
from pyglet.input.base import Device, RelativeAxis, AbsoluteAxis, Button, Joystick, Controller
from pyglet.input.base import DeviceOpenException, ControllerManager
from pyglet.input.controller import get_mapping, Relation, create_guid

_IOC_NRBITS = 8
_IOC_TYPEBITS = 8
_IOC_SIZEBITS = 14
_IOC_DIRBITS = 2

_IOC_NRSHIFT = 0
_IOC_TYPESHIFT = (_IOC_NRSHIFT + _IOC_NRBITS)
_IOC_SIZESHIFT = (_IOC_TYPESHIFT + _IOC_TYPEBITS)
_IOC_DIRSHIFT = (_IOC_SIZESHIFT + _IOC_SIZEBITS)

_IOC_NONE = 0
_IOC_WRITE = 1
_IOC_READ = 2


def _IOC(dir, type, nr, size):
    return ((dir << _IOC_DIRSHIFT) |
            (type << _IOC_TYPESHIFT) |
            (nr << _IOC_NRSHIFT) |
            (size << _IOC_SIZESHIFT))


def _IOR(type, nr, struct):
    request = _IOC(_IOC_READ, ord(type), nr, ctypes.sizeof(struct))

    def f(fileno):
        buffer = struct()
        fcntl.ioctl(fileno, request, buffer)
        return buffer

    return f


def _IOR_len(type, nr):
    def f(fileno, buffer):
        request = _IOC(_IOC_READ, ord(type), nr, ctypes.sizeof(buffer))
        fcntl.ioctl(fileno, request, buffer)
        return buffer

    return f


def _IOR_str(type, nr):
    g = _IOR_len(type, nr)

    def f(fileno, length=256):
        return g(fileno, ctypes.create_string_buffer(length)).value

    return f


def _IOW(type, nr):

    def f(fileno, buffer):
        request = _IOC(_IOC_WRITE, ord(type), nr, ctypes.sizeof(buffer))
        fcntl.ioctl(fileno, request, buffer)

    return f


# Structures from /linux/blob/master/include/uapi/linux/input.h

class Timeval(ctypes.Structure):
    _fields_ = (
        ('tv_sec', _s64),
        ('tv_usec', _s64)
    )


class InputEvent(ctypes.Structure):
    _fields_ = (
        ('time', Timeval),
        ('type', _u16),
        ('code', _u16),
        ('value', _s32)
    )


class InputID(ctypes.Structure):
    _fields_ = (
        ('bustype', _u16),
        ('vendor', _u16),
        ('product', _u16),
        ('version', _u16),
    )


class InputABSInfo(ctypes.Structure):
    _fields_ = (
        ('value', _s32),
        ('minimum', _s32),
        ('maximum', _s32),
        ('fuzz', _s32),
        ('flat', _s32),
    )


class FFReplay(ctypes.Structure):
    _fields_ = (
        ('length', _u16),
        ('delay', _u16)
    )


class FFTrigger(ctypes.Structure):
    _fields_ = (
        ('button', _u16),
        ('interval', _u16)
    )


class FFEnvelope(ctypes.Structure):
    _fields_ = [
        ('attack_length', _u16),
        ('attack_level', _u16),
        ('fade_length', _u16),
        ('fade_level', _u16),
    ]


class FFConstantEffect(ctypes.Structure):
    _fields_ = [
        ('level', _s16),
        ('ff_envelope', FFEnvelope),
    ]


class FFRampEffect(ctypes.Structure):
    _fields_ = [
        ('start_level', _s16),
        ('end_level', _s16),
        ('ff_envelope', FFEnvelope),
    ]


class FFConditionEffect(ctypes.Structure):
    _fields_ = [
        ('right_saturation', _u16),
        ('left_saturation', _u16),
        ('right_coeff', _s16),
        ('left_coeff', _s16),
        ('deadband', _u16),
        ('center', _s16),
    ]


class FFPeriodicEffect(ctypes.Structure):
    _fields_ = [
        ('waveform', _u16),
        ('period', _u16),
        ('magnitude', _s16),
        ('offset', _s16),
        ('phase', _u16),
        ('envelope', FFEnvelope),
        ('custom_len', _u32),
        ('custom_data', ctypes.POINTER(_s16)),
    ]


class FFRumbleEffect(ctypes.Structure):
    _fields_ = (
        ('strong_magnitude', _u16),
        ('weak_magnitude', _u16)
    )


class FFEffectType(ctypes.Union):
    _fields_ = (
        ('ff_constant_effect', FFConstantEffect),
        ('ff_ramp_effect', FFRampEffect),
        ('ff_periodic_effect', FFPeriodicEffect),
        ('ff_condition_effect', FFConditionEffect * 2),
        ('ff_rumble_effect', FFRumbleEffect),
    )


class FFEvent(ctypes.Structure):
    _fields_ = (
        ('type', _u16),
        ('id', _s16),
        ('direction', _u16),
        ('ff_trigger', FFTrigger),
        ('ff_replay', FFReplay),
        ('u', FFEffectType)
    )


EVIOCGVERSION = _IOR('E', 0x01, ctypes.c_int)
EVIOCGID = _IOR('E', 0x02, InputID)
EVIOCGNAME = _IOR_str('E', 0x06)
EVIOCGPHYS = _IOR_str('E', 0x07)
EVIOCGUNIQ = _IOR_str('E', 0x08)
EVIOCSFF = _IOW('E', 0x80)


def EVIOCGBIT(fileno, ev, buffer):
    return _IOR_len('E', 0x20 + ev)(fileno, buffer)


def EVIOCGABS(fileno, abs):
    buffer = InputABSInfo()
    return _IOR_len('E', 0x40 + abs)(fileno, buffer)


def get_set_bits(bytestring):
    bits = set()
    j = 0
    for byte in bytestring:
        for i in range(8):
            if byte & 1:
                bits.add(j + i)
            byte >>= 1
        j += 8
    return bits


_abs_names = {
    ABS_X: AbsoluteAxis.X,
    ABS_Y: AbsoluteAxis.Y,
    ABS_Z: AbsoluteAxis.Z,
    ABS_RX: AbsoluteAxis.RX,
    ABS_RY: AbsoluteAxis.RY,
    ABS_RZ: AbsoluteAxis.RZ,
    ABS_HAT0X: AbsoluteAxis.HAT_X,
    ABS_HAT0Y: AbsoluteAxis.HAT_Y,
}

_rel_names = {
    REL_X: RelativeAxis.X,
    REL_Y: RelativeAxis.Y,
    REL_Z: RelativeAxis.Z,
    REL_RX: RelativeAxis.RX,
    REL_RY: RelativeAxis.RY,
    REL_RZ: RelativeAxis.RZ,
    REL_WHEEL: RelativeAxis.WHEEL,
}


def _create_control(fileno, event_type, event_code):
    if event_type == EV_ABS:
        raw_name = abs_raw_names.get(event_code, 'EV_ABS(%x)' % event_code)
        name = _abs_names.get(event_code)
        absinfo = EVIOCGABS(fileno, event_code)
        value = absinfo.value
        minimum = absinfo.minimum
        maximum = absinfo.maximum
        control = AbsoluteAxis(name, minimum, maximum, raw_name)
        control.value = value
        if name == 'hat_y':
            control.inverted = True
    elif event_type == EV_REL:
        raw_name = rel_raw_names.get(event_code, 'EV_REL(%x)' % event_code)
        name = _rel_names.get(event_code)
        # TODO min/max?
        control = RelativeAxis(name, raw_name)
    elif event_type == EV_KEY:
        raw_name = key_raw_names.get(event_code, 'EV_KEY(%x)' % event_code)
        name = None
        control = Button(name, raw_name)
    else:
        value = minimum = maximum = 0  # TODO
        return None
    control._event_type = event_type
    control._event_code = event_code
    return control


event_types = {
    EV_KEY: KEY_MAX,
    EV_REL: REL_MAX,
    EV_ABS: ABS_MAX,
    EV_MSC: MSC_MAX,
    EV_LED: LED_MAX,
    EV_SND: SND_MAX,
    EV_FF: FF_MAX,
}


class EvdevDevice(XlibSelectDevice, Device):
    _fileno = None

    def __init__(self, display, filename):
        self._filename = filename

        fileno = os.open(filename, os.O_RDONLY)
        # event_version = EVIOCGVERSION(fileno).value

        self._id = EVIOCGID(fileno)
        self.id_bustype = self._id.bustype
        self.id_vendor = hex(self._id.vendor)
        self.id_product = hex(self._id.product)
        self.id_version = self._id.version

        name = EVIOCGNAME(fileno)
        try:
            name = name.decode('utf-8')
        except UnicodeDecodeError:
            try:
                name = name.decode('latin-1')
            except UnicodeDecodeError:
                pass

        try:
            self.phys = EVIOCGPHYS(fileno)
        except OSError:
            self.phys = ''
        try:
            self.uniq = EVIOCGUNIQ(fileno)
        except OSError:
            self.uniq = ''

        self.controls = []
        self.control_map = {}
        self.ff_types = []

        event_types_bits = (ctypes.c_byte * 4)()
        EVIOCGBIT(fileno, 0, event_types_bits)
        for event_type in get_set_bits(event_types_bits):
            if event_type not in event_types:
                continue
            max_code = event_types[event_type]
            nbytes = max_code // 8 + 1
            event_codes_bits = (ctypes.c_byte * nbytes)()
            EVIOCGBIT(fileno, event_type, event_codes_bits)
            if event_type == EV_FF:
                self.ff_types.extend(get_set_bits(event_codes_bits))
            else:
                for event_code in get_set_bits(event_codes_bits):
                    control = _create_control(fileno, event_type, event_code)
                    if control:
                        self.control_map[(event_type, event_code)] = control
                        self.controls.append(control)

        self.controls.sort(key=lambda c: c._event_code)
        os.close(fileno)

        super().__init__(display, name)

    def get_guid(self):
        """Get the device's SDL2 style GUID string"""
        _id = self._id
        return create_guid(_id.bustype, _id.vendor, _id.product, _id.version, self.name, 0, 0)

    def open(self, window=None, exclusive=False):
        super().open(window, exclusive)

        try:
            self._fileno = os.open(self._filename, os.O_RDWR | os.O_NONBLOCK)
        except OSError as e:
            raise DeviceOpenException(e)

        pyglet.app.platform_event_loop.select_devices.add(self)

    def close(self):
        super().close()

        if not self._fileno:
            return

        pyglet.app.platform_event_loop.select_devices.remove(self)
        os.close(self._fileno)
        self._fileno = None

    def get_controls(self):
        return self.controls

    # Force Feedback methods

    def ff_upload_effect(self, structure):
        os.write(self._fileno, structure)

    # XlibSelectDevice interface

    def fileno(self):
        return self._fileno

    def poll(self):
        return False

    def select(self):
        if not self._fileno:
            return

        try:
            events = (InputEvent * 64)()
            bytes_read = os.readv(self._fileno, events)
        except OSError:
            self.close()
            return

        n_events = bytes_read // ctypes.sizeof(InputEvent)
        for event in events[:n_events]:
            try:
                control = self.control_map[(event.type, event.code)]
                control.value = event.value
            except KeyError:
                pass


class FFController(Controller):
    """Controller that supports force-feedback"""
    _fileno = None
    _weak_effect = None
    _play_weak_event = None
    _stop_weak_event = None
    _strong_effect = None
    _play_strong_event = None
    _stop_strong_event = None

    def open(self, window=None, exclusive=False):
        super().open(window, exclusive)
        self._fileno = self.device.fileno()
        # Create Force Feedback effects & events when opened:
        # https://www.kernel.org/doc/html/latest/input/ff.html
        self._weak_effect = FFEvent(FF_RUMBLE, -1)
        EVIOCSFF(self._fileno, self._weak_effect)
        self._play_weak_event = InputEvent(Timeval(), EV_FF, self._weak_effect.id, 1)
        self._stop_weak_event = InputEvent(Timeval(), EV_FF, self._weak_effect.id, 0)

        self._strong_effect = FFEvent(FF_RUMBLE, -1)
        EVIOCSFF(self._fileno, self._strong_effect)
        self._play_strong_event = InputEvent(Timeval(), EV_FF, self._strong_effect.id, 1)
        self._stop_strong_event = InputEvent(Timeval(), EV_FF, self._strong_effect.id, 0)

    def rumble_play_weak(self, strength=1.0, duration=0.5):
        effect = self._weak_effect
        effect.u.ff_rumble_effect.weak_magnitude = int(max(min(1.0, strength), 0) * 0xFFFF)
        effect.ff_replay.length = int(duration * 1000)
        EVIOCSFF(self._fileno, effect)
        self.device.ff_upload_effect(self._play_weak_event)

    def rumble_play_strong(self, strength=1.0, duration=0.5):
        effect = self._strong_effect
        effect.u.ff_rumble_effect.strong_magnitude = int(max(min(1.0, strength), 0) * 0xFFFF)
        effect.ff_replay.length = int(duration * 1000)
        EVIOCSFF(self._fileno, effect)
        self.device.ff_upload_effect(self._play_strong_event)

    def rumble_stop_weak(self):
        self.device.ff_upload_effect(self._stop_weak_event)

    def rumble_stop_strong(self):
        self.device.ff_upload_effect(self._stop_strong_event)


class EvdevControllerManager(ControllerManager, XlibSelectDevice):

    def __init__(self, display=None):
        super().__init__()
        self._display = display
        self._devices_file = open('/proc/bus/input/devices')
        self._device_names = self._get_device_names()
        self._controllers = {}
        self._thread_pool = ThreadPoolExecutor(max_workers=1)

        for name in self._device_names:
            path = os.path.join('/dev/input', name)
            try:
                device = EvdevDevice(self._display, path)
            except OSError:
                continue
            controller = _create_controller(device)
            if controller:
                self._controllers[name] = controller

        pyglet.app.platform_event_loop.select_devices.add(self)

    def __del__(self):
        self._devices_file.close()

    def fileno(self):
        """Allow this class to be Selectable"""
        return self._devices_file.fileno()

    @staticmethod
    def _get_device_names():
        return {name for name in os.listdir('/dev/input') if name.startswith('event')}

    def _make_device_callback(self, future):
        name, device = future.result()
        if not device:
            return

        if name in self._controllers:
            controller = self._controllers.get(name)
        else:
            controller = _create_controller(device)
            self._controllers[name] = controller

        if controller:
            # Dispatch event in main thread:
            pyglet.app.platform_event_loop.post_event(self, 'on_connect', controller)

    def _make_device(self, name, count=1):
        path = os.path.join('/dev/input', name)
        while count > 0:
            try:
                return name, EvdevDevice(self._display, path)
            except OSError:
                if count > 0:
                    time.sleep(0.1)
                count -= 1
        return None, None

    def select(self):
        """Triggered whenever the devices_file changes."""
        new_device_files = self._get_device_names()
        appeared = new_device_files - self._device_names
        disappeared = self._device_names - new_device_files
        self._device_names = new_device_files

        for name in appeared:
            future = self._thread_pool.submit(self._make_device, name, count=10)
            future.add_done_callback(self._make_device_callback)

        for name in disappeared:
            controller = self._controllers.get(name)
            if controller:
                self.dispatch_event('on_disconnect', controller)

    def get_controllers(self) -> List[Controller]:
        return list(self._controllers.values())


def get_devices(display=None):
    _devices = {}
    base = '/dev/input'
    for filename in os.listdir(base):
        if filename.startswith('event'):
            path = os.path.join(base, filename)
            if path in _devices:
                continue

            try:
                _devices[path] = EvdevDevice(display, path)
            except OSError:
                pass

    return list(_devices.values())


def _create_joystick(device):
    # Look for something with an ABS X and ABS Y axis, and a joystick 0 button
    have_x = False
    have_y = False
    have_button = False
    for control in device.controls:
        if control._event_type == EV_ABS and control._event_code == ABS_X:
            have_x = True
        elif control._event_type == EV_ABS and control._event_code == ABS_Y:
            have_y = True
        elif control._event_type == EV_KEY and control._event_code in (BTN_JOYSTICK, BTN_GAMEPAD):
            have_button = True
    if not (have_x and have_y and have_button):
        return

    return Joystick(device)


def get_joysticks(display=None):
    return [joystick for joystick in
            [_create_joystick(device) for device in get_devices(display)]
            if joystick is not None]


def _detect_controller_mapping(device):
    # If no explicit mapping is available, we can
    # detect it from the Linux gamepad specification:
    # https://www.kernel.org/doc/html/v4.13/input/gamepad.html
    # Note: legacy device drivers don't always adhere to this.
    mapping = dict(guid=device.get_guid(), name=device.name)

    _aliases = {BTN_MODE: 'guide', BTN_SELECT: 'back', BTN_START: 'start',
                BTN_SOUTH: 'a', BTN_EAST: 'b', BTN_WEST: 'x', BTN_NORTH: 'y',
                BTN_TL: 'leftshoulder', BTN_TR: 'rightshoulder',
                BTN_TL2: 'lefttrigger', BTN_TR2: 'righttrigger',
                BTN_THUMBL: 'leftstick', BTN_THUMBR: 'rightstick',
                BTN_DPAD_UP: 'dpup', BTN_DPAD_DOWN: 'dpdown',
                BTN_DPAD_LEFT: 'dpleft', BTN_DPAD_RIGHT: 'dpright',

                ABS_HAT0X: 'dpleft',  # 'dpright',
                ABS_HAT0Y: 'dpup',    # 'dpdown',
                ABS_Z: 'lefttrigger', ABS_RZ: 'righttrigger',
                ABS_X: 'leftx', ABS_Y: 'lefty', ABS_RX: 'rightx', ABS_RY: 'righty'}

    button_controls = [control for control in device.controls if isinstance(control, Button)]
    axis_controls = [control for control in device.controls if isinstance(control, AbsoluteAxis)]
    hat_controls = [control for control in device.controls if control.name in ('hat_x', 'hat_y')]

    for i, control in enumerate(button_controls):
        name = _aliases.get(control._event_code)
        if name:
            mapping[name] = Relation('button', i)

    for i, control in enumerate(axis_controls):
        name = _aliases.get(control._event_code)
        if name:
            mapping[name] = Relation('axis', i)

    for i, control in enumerate(hat_controls):
        name = _aliases.get(control._event_code)
        if name:
            index = 1 + i << 1
            mapping[name] = Relation('hat0', index)

    return mapping


def _create_controller(device):
    for control in device.controls:
        if control._event_type == EV_KEY and control._event_code == BTN_GAMEPAD:
            break
    else:
        return None     # Game Controllers must have a BTN_GAMEPAD

    mapping = get_mapping(device.get_guid())
    if not mapping:
        warnings.warn(f"Warning: {device} (GUID: {device.get_guid()}) "
                      f"has no controller mappings. Update the mappings in the Controller DB.\n"
                      f"Auto-detecting as defined by the 'Linux gamepad specification'")
        mapping = _detect_controller_mapping(device)

    if FF_RUMBLE in device.ff_types:
        return FFController(device, mapping)
    else:
        return Controller(device, mapping)


def get_controllers(display=None):
    return [controller for controller in
            [_create_controller(device) for device in get_devices(display)]
            if controller is not None]
